Recent Developments in Antioxidant Screening of Herbs

Herbs remain a promising source of natural antioxidants which can prolong the shelf life of food. Examples include rosemary, sage, olives, tea and wine extracts. For quality control and possible further improvement of antioxidant extracts, knowledge about the active principles, their stability and their mode of action is a sine qua non. Unfortunately the activity-guided-fractionations which are necessary for this purpose are time-consuming, difficult and expensive. On-line HPLC screening is a new, rapid way for pinpointing active constituents without their prior isolation. The development of an on-line radical scavening assay based on the model radicals DPPH or ABTS will be presented. Applications with Lithuanian herbs are discussed. Basic characteristics such as sensitivity as well as shortcomings and possible future improvements will be mentioned.

Teris A. van Beek is associate professor in natural products chemistry at Wageningen University, The Netherlands. Currently he teaches chromatography. His entire scientific career he has performed research on natural products like antimicrobial alkaloids, terpenes, essential oils, anticancer drugs, dyes, pheromones, antifungal peptides, sugar-binding proteins and antioxidants. He is most interested in their isolation, purification, separation and identification, or in other words analytical chemical aspects of natural products. New or improved phytochemical methods can lead to faster analyses, improved quality control or new uses of plant extracts. He is author, co-author or editor of 150+ papers in international refereed journals or books and was the winner of the Research Award of the Phytochemical Society of Europe in 2000. He is a member of the editorial boards of the Journal of Chromatography A and Phytochemical Analysis.